Re: [PATCH] hashed device lookup (Does NOT meet Linus' sumission

Matti Aarnio
2001-01-07T15:33:35Z

On Sun, Jan 07, 2001 at 01:42:50PM +0000, Alan Cox wrote:
> > + * NOTE: That is no longer true with the addition of VLAN tags. Not
> > + * sure which should go first, but I bet it won't make much
> > + * difference if we are running VLANs. The good news is that
>
> It makes a lot of difference tha the vlan goes 2nd. Most sane people wont
> have vlans active on a high load interface.

VLAN tag header appears as Layer-3 protocol, which then
causes loop into VLAN reception code and back to generic
Layer-3 receiver.

I just tried to pull data from another machine, which
is on normal port thru VLAN trunking port to receiving
machine, and got fast-ether at wire speed. (As near as
ncftp's 11.11 MB/sec is wirespeed..)

> So fix the algorithm. You want the list sorted at this point, or to generate
> a bitmap of free/used entries and scan the list then scan the map
>
> Question: How do devices with hardware vlan support fit into your model ?

Hardware VLAN support at several network cards is just
to recognize VLAN tags, and then do the right thing
( = skip 4 bytes ) when doing TCP/UDP checksum.

> Alan

/Matti Aarnio